1. Field of the Invention
The present invention relates to an electronic device that includes a printed circuit board, a connector mounted on the printed circuit board, and a casing for housing the printed circuit board and a part of the connector.
2. Description of the Related Art
According to the prior art, an electronic device includes a printed circuit board, a connector mounted on the printed circuit board, and a casing for housing the printed circuit.
For example, in each electronic control device disclosed in U.S. Pat. No. 6,707,678 (corresponding to JP-A-2001-85858 and JP-A-2001-85866), a casing includes a casing body and a cover. The casing body has an opening portion on an upper surface portion and houses an electronic circuit unit therein. The cover is disposed to close the opening portion of the casing body. The casing body has a connector opening at a sidewall thereof. The connector opening communicates with the opening portion. A part of the connector protrudes from the connector opening to an outside of the casing in a state where the printed circuit board is housed in the casing. A sealing member is disposed between an open edge portion of the casing body and a flange portion of the cover and between an inner surface of the connector opening and an outer surface of the connector, respectively.
In one electronic control device disclosed in U.S. Pat. No. 6,707,678, the connector has a groove at an upper surface thereof and a protruding portion at a lower surface thereof. However, side surfaces of the connector are substantially flat. In addition, side portions of the connector opening that face the side surfaces of the connector are also substantially flat. Thus, in a case where a sealing part has a substantially constant width, leak paths at a part of the sealing part located between the side surfaces of the connector and the side portions of the connector opening are shorter than a leak path at the other part of the sealing part. Furthermore, contact areas between the sealing member and the side surfaces of the connector and the constant areas between the sealing member and the side portions of the connector opening are reduced compared with the other portion. Thus, it is difficult to improve a sealing property, i.e., waterproof property of the casing while reducing a dimension of the electronic control device in a direction where the connector is fitted with an external connector.
In another electronic control device disclosed in U.S. Pat. No. 6,707,678, one of the side surfaces of the connector and the side portions of the connector opening are substantially flat and the other one have protruding portions. The protruding portions are disposed to provide predetermined clearances between the side surfaces of the connector and the side portions of the connector opening. Thus, even though the protruding portions are disposed, the lengths of the leak paths are not increased and the constant areas with the sealing member change little. In addition, in a case where the protruding portion comes in contact with the flat portion only one side due to a tolerance or a displacement, the clearance on the other side may become large. Thereby, the sealing member may run short and the sealing property may be reduced.